The present invention relates to improvements in conventional and tubular bicycle tires and also to the method of manufacturing such tires.
It is known that racing cycle tires, also called tubular tires, comprise as a rule an inner tube enclosed in a textile casing or cover over which a cured rubber tread is superposed.
Since it is a constant concern in the manufacture of bicycle tires to minimize their rolling resistance and inertia, extremely lightweight tubular tires have been developed which comprise a generally thin outer peripheral tread. Thus, tubular tires of very reduced diameter are produced, but the smaller this diameter or cross-sectional dimension, the higher the inflation pressure. As a result, puncture hazards increase considerably, and this constitutes a major inconvenience for racers.
The recent trend among an increasing number of cyclists for adopting tubular tires instead of conventional tires is attended by the same inconveniences as those known to racers, not so much on the road since the ordinary cyclist is in less of a hurry than racers, but at home where tubular tire repair constitutes a tedious and time-consuming operation.
All these inconveniences have led to various attempts to find some means capable of limiting the penetration through the tread of foreign, pointed bodies such as are currently found on road surfaces, for example flints, glass splinters, nails, glass or metal fragments, etc. Such means consisted mainly in interposing a reinforcing element in the tread structure for preventing such penetration, this element consisting in general of tightly woven cotton fabric. However, notwithstanding the superposition of two or more fabric layers for constituting the reinforcing element, the desired result is attained only partly.
This prior art solution was improved notably by replacing cotton with stronger textile materials, such as polyamids ("Nylon"), or polyesters ("Tergal") already widely used in the tire industry.